Acoustic load mitigator

Abstract

A system for reducing an acoustic load of a fluid flow includes a first pipe. The first pipe includes a first end and a second end and a first aperture and a second aperture, the first and second apertures being intermediate the first and second ends. A second pipe includes a first end and a second end and a third aperture intermediate the first and second ends. The second pipe is connected at its first end to the first pipe at the first aperture. A bypass pipe includes a first end connected to the second aperture of the first pipe and a second end connected to the third aperture of the second pipe. A method of reducing an acoustic load of a flow in a standpipe connected to a first pipe configured to carry a main flow includes providing a bypass flow from the first pipe to the standpipe.

Description

BACKGROUND OF THE INVENTION[0001]The present invention relates generally to nuclear reactors, and more particularly to mitigating acoustic loads in a nuclear reactor.[0002]A reactor pressure vessel (RPV) of a boiling water reactor (BWR) typically has a generally cylindrical shape and is closed at both ends, e.g., by a bottom head and a removable top head. A top guide typically is spaced above a core plate within the RPV. A core shroud, or shroud, typically surrounds the core and is supported by a shroud support structure. Particularly, the shroud has a generally cylindrical shape and surrounds both the core plate and the top guide. There is a space or annulus located between the cylindrical reactor pressure vessel and the cylindrically shaped shroud.[0003]Heat is generated within the core and water circulated up through the core is at least partially converted to steam. Steam separators separate the steam and the water. Residual water is removed from the steam by steam dryers locate...

AI Technical Summary

Benefits of technology

[0010]In another embodiment of the invention, a method of reducing an acoustic load of a flow in a standpipe connected to a first pipe configured to carry a main flow comprises providing a bypass flow from the first pipe to the standpipe.

Problems solved by technology

The flow of steam through the dryers can be unbalanced or mismatched, with much of the steam flow preferentially passing through the top of the dryer vanes.

At increased power levels of the reactor, increased steam flow may cause the steam velocity to exceed the breakthrough velocity in local regions of the dryer vanes.

Wet steam that breaks through, or exits the dryer, then can cause undesirable effects in the rest of the power plant.

In addition to the potential for erosion of the metal components, the excess moisture can transport activated particulates from the reactor to the pipes, turbines and heat exchangers which are downstream of the separator which can increase the dose rate in the turbine hall, and make equipment maintenance more difficult.

One of the sources of loading that has destroyed or damaged equipment is acoustic resonance of the fluid inside a standoff pipe, such as a safety relief valve.

The safety relieve valve, or valves, with steam flow past their entrances, and the acoustic resonance which naturally occurs, causes acoustic pressures to travel upstream, causing damage to devices, for example, the steam dryers.

However, the Helmholtz resonator is a large cantilevered bottle-shaped device which is difficult to support in the environment of a nuclear power generating station.

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